DKK1 and carcinoma of esophagus: The expression and roles of DKK1 is different in various cancers, current studies have reported that overexpression of DKK1 is found in many malignant tumors including breast cancer, lung cancer, esophageal carcinomas and hepatocellular carcinoma (HCC)[11-15], indicating a potential oncogenic function of DKK1[16].